Rebecca Gilman is an American dramatist who writes about hot topics with unsensational honesty. Having dealt with stalking in Boy Gets Girl and racism in Spinning into Butter, she now tackles a middle-aged cop's fixation with a young prostitute. But what might be the cue in Hollywood for soft-porn romance, here becomes a ruefully observant study of shared solitude and social determinism.

Curt and a police colleague take part in an abortive raid on a massage parlour in a deeply religious midwest city. But, although Curt is going steady with a middle-class art teacher, he finds himself inexorably drawn to a novice sex-worker, Sandy, and sets out on a self-destructive mission to rescue her. What Gilman shows, with quiet compassion, is the instinctive kinship between two screwed up people – one scene in which Curt, whose dream is to work on a nature reserve, enlists Sandy to help him identify leaf patterns is a shining example of how to reveal unspoken emotion through action. But although Gilman writes well about loneliness, she does so without sentimentality. As Sandy persistently reminds Curt, "I want to do what I do."

Even if there is something schematic about the sub-plot in which Curt's colleague settles down with a happy hooker, Ché Walker's production hits exactly the right note of pained intimacy. James Hillier as the aspirational working-class Curt and Clare Latham as the better-educated and more business-like Sandy also admirably convey a growing mutual attraction. And Samantha Coughlan is suitably condescending as Curt's girlfriend, brusquely telling him, "It's amazing you're not in jail, given where you come from." Which neatly underscores Gilman's point that America, at its heart, is a profoundly class-ridden society.